Phonograph tone arm system

Abstract

An improved phonograph tone arm device is disclosed in which the pickup, including the stylus, is supported on a low friction air-bearing support which provides for essentially frictionless movement of the tone arm and pickup both in horizontal linear travel and vertical pivoting to assure proper stylus pressure. The tone arm support system includes a support member having an upper surface which is shaped as a right circular trough or cylinder section and a floating member which has a juxtaposed matching convex or concave lower surface. A recess in the lower surface of the floating member forms a plenum to which air is supplied from one or more openings in the support member. The length of the plenum is such that the supply openings are always beneath the plenum confines during the full traverse of the stylus across a record to be played to minimize the amount of air required and maximize uniformity of support for the floating member. Alternate embodiments allow either the upper or lower surface of the record to be played.

The embodiments of the invention in which an exclusive property or right is claimed are defined as follows: 
     
       1. A phonograph tone arm system comprising: low friction tone arm support means, said support means further comprising: support member defining a linear substantially horizontal path of travel having an axially curvilinear upper surface in the form of a circular cylinder segment;   floating member supported above and disposed to travel along said support member, said floating member having an axially curvilinear lower surface juxtaposed and matching the shape of said upper surface of said support member, said lower surface of said floating member having an elongated recessed area therein defining with said upper surface of said support member a hollow plenum;   fluid supply means for supplying an amount of pressurized gaseous fluid to said plenum chamber through at least one fluid supply opening in said support member sufficient to produce free flotation of said floating member above said support member and wherein the longitudinal dimension of said plenum in cooperation with the said at least one fluid supply opening is such that the said at least one fluid supply opening is in communication with said plenum at all times during normal linear displacement of said floating member to play a storage medium such that fluid escapes only about the peripheral edges of said plenum;     tone arm means carried by said floating member said tone arm means including pickup means adapted to traverse a phonograph record along a radial path during the linear displacement of said floating member;   signal conducting means for conducting signals from said pickup means to a signal processing means.   
     
     
       2. The apparatus of claim 1 wherein the supper surface of said support member is in the shape of a concave circular trough and the juxtaposed lower surface of said flotating member has a matching convex form peripheral to said recess and wherein said support member is disposed beneath the level of a phonograph record to be played such that said pickup means may play the lower surface of a phonograph record. 
     
     
       3. The apparatus of claim 1 wherein the upper surfaces of said support member is convex circular cylinder segment and the juxtaposed lower surface of said flotating member has a matching concave form peripheral to said recess such that said pickup means may play the upper surface of a phonograph record. 
     
     
       4. The apparatus of claim 1 wherein the axis of said circular cylinder of said support member is coincident with the plane of the phonograph record to be played. 
     
     
       5. The apparatus of claim 1 wherein said tone arm and said floating member comprise a unitized structure. 
     
     
       6. The apparatus of claim 1 including flexible electrical conduit means for conducting the signals from said pickup to an amplifier system. 
     
     
       7. The apparatus of claim 1 wherein said fluid supply means further comprises: motor driven positive displacement air pump means;   expanding accumulator means for storing a supply of air;   conduit means for supplying air from said accumulator to said support means.   
     
     
       8. The apparatus of claim 7 wherein air pump means includes a plurality of bellows sequentially driven by a common crankshaft. 
     
     
       9. The apparatus of claim 8 wherein said air pump means is integral with said phonograph tone arm system.